Long-Term Debt and Credit Facility - Additional Information (Details)	1 Months Ended	3 Months Ended
	Oct. 31, 2015 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2017	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Amount retired under prior credit facility	$ 344,700,000
Proceeds from line of credit		$ 10,000,000	$ 34,000,000
Debt designated as third-party debt		9,600,000			$ 9,600,000
Third-party notes and bank debt held		300,000			300,000
Long-term debt, fair value		$ 374,000,000			366,000,000
2015 Interest Rate Swap
Debt Instrument [Line Items]
Notional Amount	$ 262,500,000
Fixed interest rate	1.46%
2015 Credit Facility
Debt Instrument [Line Items]
Senior secured credit facility	$ 650,000,000
Maximum borrowing capacity	$ 350,000,000
Term of revolving line of credit	5 years
Term of term loan facility	5 years
Interest rate at period end		3.26%
Secured debt outstanding		$ 323,800,000			328,100,000
Proceeds from line of credit		46,000,000
Letters of credit issued and outstanding		$ 32,700,000
Line of credit					$ 36,000,000
Portion of amortization of term loan	$ 262,500,000
Initial maximum financial leverage ratio		3.75
Actual financial leverage ratio		3.10
Remaining borrowing capacity		$ 80,900,000
Minimum permitted fixed charge coverage ratio		1.25
Actual fixed charge coverage ratio		1.72
2015 Credit Facility | Insurance Carriers Collateral
Debt Instrument [Line Items]
Letters of credit issued and outstanding		$ 15,100,000
2015 Credit Facility | Work Performance Obligations
Debt Instrument [Line Items]
Letters of credit issued and outstanding		$ 17,500,000
2015 Credit Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		1.25%
2015 Credit Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate		2.25%
2015 Credit Facility | Underground Solutions
Debt Instrument [Line Items]
Initial maximum financial leverage ratio		4.00
Credit facility maximum consolidated leverage ratio period		1 year
Scenario, Forecast | 2015 Credit Facility
Debt Instrument [Line Items]
Initial maximum financial leverage ratio				3.50
Line of Credit | 2015 Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 300,000,000
Proceeds from line of credit		$ 10,000,000